Apparatus and a method for cleaving thin rods

Abstract

A method for cleaving thin rods of glass or quartz with a rod cleaving blade ( 27 ) and body ( 28 ) carrying the blade, is provided. The body ( 28 ) is of material varying in length through application of electric and/or magnetic fields. Driving force ( 31, 33 ) achieves relatively steady movement of the blade ( 27 ) towards a desired cleaving point and relatively steady small-amplitude vibratory component of movement towards and away from the cleaving point superimposed to the relatively steady movement, by influencing the body ( 28 ) electrically and/or magnetically. The blade is driven to vibrate with a frequency below 1 kHz during cleaving operation.

1. A method of cleaving a thin rod of glass or quartz having a diameter below 1 mm, comprising the steps of:
 supporting said rod ( 3 ) in a working position; 
 bringing about a relatively steady movement of a cleaving blade ( 27 ) towards a point of lateral contact with said rod; and 
 superimposing on said relatively steady movement of the blade a relatively small-amplitude vibratory component of movement, said vibratory component being towards and away from the axis of the rod, wherein said vibratory component of movement having a frequency below 1 kHz is applied to the blade; and, 
 further comprising the step of clamping, prior to the supporting step, in which said rod ( 3 ) is clamped in two mutually-spaced clamping locations for holding the rod ( 3 ) extended between these two clamping locations in said working position, and in which the clamping in a first clamping location is carried out by translationally moving a first clamping member ( 22 ) with a clamp face ( 23 ) of substantially V-groove type ( 24 ), for receiving the rod ( 3 ) in the groove ( 24 ), towards a second clamping member ( 21 ) having a flat opposing clamp face ( 25 ) for retaining the rod ( 3 ) in the groove ( 24 ) for clamping the rod ( 3 ). 
 
     
     
       2. A method according to  claim 1 , wherein it further comprises a step of adjusting the position of a rod ( 3 ) being clamped in only one of said two clamping locations before clamping it according to said clamping step in the other clamping location, in which at least one member ( 14 ) having at least one inclined surface ( 17 ,  18 ) is moved laterally towards said rod with the inclined surface into abutment against the rod for influencing the rod by sliding thereof upon said surface for reaching a position desired for said other clamping location. 
     
     
       3. A method according to  claim 2 , wherein in said adjusting step one or more said members ( 14 ) having together at least two said inclined surfaces ( 17 ,  18 ), which are oppositely inclined with respect to a plane including said two clamping locations, are moved laterally towards said rod ( 3 ) for moving the rod to a seat in an intersection between said two inclined surfaces as seen in the direction from one clamping location to the other. 
     
     
       4. A method according to  claim 1 , wherein it further comprises a step, carried out prior to said supporting step, of clamping said rod ( 3 ) in two mutually-spaced clamping locations for holding the rod extended between these two clamping locations, after this clamping step at least one of said two clamping locations is moved in the longitudinal direction of said clamped rod for increasing the distance to the other clamping location and by that applying a longitudinal tension load to the rod, and said tension load is measured and the movement of the clamping locations apart is controlled on the basis of information about the tension load measured for adjusting the tension load. 
     
     
       5. A method according to  claim 1 , wherein it comprises a step of clamping said rod ( 3 ), carried out prior to said supporting step, and in which said rod is clamped in two mutually-spaced clamping locations for holding the rod extended between these two clamping locations in said working position, after said cleaving operation has been completed said blade ( 27 ) is moved into contact with a waist rod portion ( 39 ) resulting from said cleaving for applying a force onto said waist rod portion at the end thereof located at a point for said cleaving, and a releasing of the clamping action in the clamping point of said waist rod portion is co-ordinated with a suction away of that portion promoted by said force applied through the blade on said end of the waist rod portion. 
     
     
       6. A method according to  claim 5 , wherein the clamping location belonging to the rod portion for later use is after the cleaving operation moved in the direction away from said cleaving point before the blade ( 27 ) is moved into contact with said end of the waist rod portion ( 39 ). 
     
     
       7. A method according to  claim 1 , comprising the step of vibrating the blade ( 27 ) at a frequency below 750 Hz. 
     
     
       8. A method according to  claim 7 , wherein the blade ( 27 ) is vibrated at a frequency between 100 and 700 Hz. 
     
     
       9. A method according to  claim 8 , wherein the blade ( 27 ) is vibrated at a frequency between 250 and 450 Hz. 
     
     
       10. A method according to  claim 1 , comprising the step of cleaving rods having a diameter below 600 μm. 
     
     
       11. A method according to  claim 10 , comprising the step of cleaving rods having a diameter below 300 μm. 
     
     
       12. A method according to  claim 11 , comprising the step of cleaving rods having a diameter between 50 and 200 μm. 
     
     
       13. A method according to  claim 1 , comprising the step of cleaving the rods ( 3 ) to provide end surfaces within ±0.17° from being exactly perpendicular to a longitudinal axis of the rods ( 3 ). 
     
     
       14. A method according to  claim 13 , wherein the rods ( 3 ) are always cleaved to provide end surfaces within ±0.17° from being exactly perpendicular to a longitudinal axis of the rods ( 3 ). 
     
     
       15. A method according to  claim 1 , comprising the step of moving said blade ( 27 ) comparatively far in a direction toward said rod ( 3 ) in a period of time between two subsequent oscillations at a given velocity of the relatively steady movement when compared with frequency above 1 KHz,
 thus ensuring cleaving of said rod ( 3 ) with minimal strokes and improved optical flatness of a cleaved rod ( 3 ). 
 
     
     
       16. A method according to  claim 1 , wherein the relatively steady movement of the blade ( 27 ) towards the point of lateral contact with the rod is along an arc-like path, and
 the blade ( 27 ) hits the rod ( 3 ) in a direction making an angle with the rod ( 3 ) differing from 90° for cutting the rod ( 3 ) in this direction.